ABSTRACT
SCIENTIFIC BACKGROUND Botulinum toxin (BoTN) is produced by Clostridium botulinum as a complex mixture of seven neurotoxic polypeptides and nontoxic protein components. Synthesized as a single-chain polypeptide of ~150 kD, BoTN has relatively little potency until it is cleaved by trypsin or bacterial enzymes into two chains: a heavy chain of 100 kD responsible for binding to the target structure and a light chain of 50 kD known as the toxifying chain. BoTN serotypes act as zinc-dependent endopeptidases. The best characterized toxins are BoTN-A and BoTN-B, both are used therapeutically and commercially available [1,2].
